/*--------------------------------------------------------------------------
 * gin.h
 *      Public header file for Generalized Inverted Index access method.
 *
 *    Copyright (c) 2006-2017, PostgreSQL Global Development Group
 *
 *    src/include/access/gin.h
 *--------------------------------------------------------------------------
 */
#ifndef GIN_H
#define GIN_H

#include "access/xlogreader.h"
#include "lib/stringinfo.h"
#include "storage/block.h"
#include "utils/relcache.h"


/*
 * amproc indexes for inverted indexes.
 */
#define GIN_COMPARE_PROC               1
#define GIN_EXTRACTVALUE_PROC           2
#define GIN_EXTRACTQUERY_PROC           3
#define GIN_CONSISTENT_PROC               4
#define GIN_COMPARE_PARTIAL_PROC       5
#define GIN_TRICONSISTENT_PROC           6
#define GINNProcs                       6

/*
 * searchMode settings for extractQueryFn.
 */
#define GIN_SEARCH_MODE_DEFAULT            0
#define GIN_SEARCH_MODE_INCLUDE_EMPTY    1
#define GIN_SEARCH_MODE_ALL                2
#define GIN_SEARCH_MODE_EVERYTHING        3    /* for internal use only */

/*
 * GinStatsData represents stats data for planner use
 */
typedef struct GinStatsData
{
    BlockNumber nPendingPages;
    BlockNumber nTotalPages;
    BlockNumber nEntryPages;
    BlockNumber nDataPages;
    int64        nEntries;
    int32        ginVersion;
} GinStatsData;

/*
 * A ternary value used by tri-consistent functions.
 *
 * For convenience, this is compatible with booleans. A boolean can be
 * safely cast to a GinTernaryValue.
 */
typedef char GinTernaryValue;

#define GIN_FALSE        0        /* item is not present / does not match */
#define GIN_TRUE        1        /* item is present / matches */
#define GIN_MAYBE        2        /* don't know if item is present / don't know
                                 * if matches */

#define DatumGetGinTernaryValue(X) ((GinTernaryValue)(X))
#define GinTernaryValueGetDatum(X) ((Datum)(X))
#define PG_RETURN_GIN_TERNARY_VALUE(x) return GinTernaryValueGetDatum(x)

/* GUC parameters */
extern PGDLLIMPORT int GinFuzzySearchLimit;
extern int    gin_pending_list_limit;

/* ginutil.c */
extern void ginGetStats(Relation index, GinStatsData *stats);
extern void ginUpdateStats(Relation index, const GinStatsData *stats);

#endif                            /* GIN_H */
